It is known that, in known herbicides, herbicidal compounds comprising difluoromethanesulfonylanilide derivatives represented by
wherein R1 is a hydrogen atom, an alkyl group, or an alkoxyalkyl group, or a salt thereof have high herbicidal effects at low doses on annual weeds such as Echinochloa crus-galli, Cyperus difformis, Monochoria vaginalis, Ammannia multiflora and the like, and perennial weeds, such as Eleocharis acicularis, Sagittaria pygmaea, Sagittaria trifolia and the like or, in particular, paddy weeds, and have broad herbicidal spectra (JP2000-44546A).
However, this herbicidal compound may be sometimes phytotoxic to rice, when applied under inappropriate conditions of weather, soil, control of water in the paddy field and the like or, when applied in excessive amounts unwillingly or accidentally.
In addition, an excessive application of this herbicidal compound may cause a risk of increased load on the environments due to flow-out to or residual amount in the environments including rivers, underground water, soils and others.
Therefore, the technologies are desired for employing herbicides capable of attaining increased safety to rice and sustainedly exhibiting the effectiveness over a long period of time along with alleviation of the load on the environment.